public static AASLunarEclipseDetails CalculateLunar(double k)
{
#if DEBUG
double intp = 0;
bool bSolarEclipse = (AASMath.modF(k, ref intp) == 0);
if (bSolarEclipse)
{
throw new NotSupportedException("bSolarEclipse must be false for the operation to complete successfully.");
}
#endif
double Mdash = 0;
AASSolarEclipseDetails solarDetails = Calculate(k, ref Mdash);
//What will be the return value
AASLunarEclipseDetails details = new AASLunarEclipseDetails
{
bEclipse = solarDetails.Flags != 0,
F = solarDetails.F,
gamma = solarDetails.gamma,
TimeOfMaximumEclipse = solarDetails.TimeOfMaximumEclipse,
u = solarDetails.u
};
if (details.bEclipse)
{
details.PenumbralRadii = 1.2848 + details.u;
details.UmbralRadii = 0.7403 - details.u;
double fgamma = Math.Abs(details.gamma);
details.PenumbralMagnitude = (1.5573 + details.u - fgamma) / 0.5450;
details.UmbralMagnitude = (1.0128 - details.u - fgamma) / 0.5450;
double p = 1.0128 - details.u;
double t = 0.4678 - details.u;
double n = 0.5458 + 0.0400 * Math.Cos(Mdash);
double gamma2 = details.gamma * details.gamma;
double p2 = p * p;
if (p2 >= gamma2)
{
details.PartialPhaseSemiDuration = 60 / n * Math.Sqrt(p2 - gamma2);
}
double t2 = t * t;
if (t2 >= gamma2)
{
details.TotalPhaseSemiDuration = 60 / n * Math.Sqrt(t2 - gamma2);
}
double h = 1.5573 + details.u;
double h2 = h * h;
if (h2 >= gamma2)
{
details.PartialPhasePenumbraSemiDuration = 60 / n * Math.Sqrt(h2 - gamma2);
}
}
return(details);
}
private static AASSolarEclipseDetails Calculate(double k, ref double Mdash)
{
//Are we looking for a solar or lunar eclipse
double intp = 0;
bool bSolarEclipse = (AASMath.modF(k, ref intp) == 0);
//What will be the return value
AASSolarEclipseDetails details = new AASSolarEclipseDetails();
//convert from K to T
double T = k / 1236.85;
double T2 = T * T;
double T3 = T2 * T;
double T4 = T3 * T;
double E = 1 - 0.002516 * T - 0.0000074 * T2;
double M = AASCoordinateTransformation.MapTo0To360Range(2.5534 + 29.10535670 * k - 0.0000014 * T2 - 0.00000011 * T3);
M = AASCoordinateTransformation.DegreesToRadians(M);
Mdash = AASCoordinateTransformation.MapTo0To360Range(201.5643 + 385.81693528 * k + 0.0107582 * T2 + 0.00001238 * T3 - 0.000000058 * T4);
Mdash = AASCoordinateTransformation.DegreesToRadians(Mdash);
double omega = AASCoordinateTransformation.MapTo0To360Range(124.7746 - 1.56375588 * k + 0.0020672 * T2 + 0.00000215 * T3);
omega = AASCoordinateTransformation.DegreesToRadians(omega);
double F = AASCoordinateTransformation.MapTo0To360Range(160.7108 + 390.67050284 * k - 0.0016118 * T2 - 0.00000227 * T3 + 0.00000001 * T4);
details.F = F;
double Fdash = F - 0.02665 * Math.Sin(omega);
F = AASCoordinateTransformation.DegreesToRadians(F);
Fdash = AASCoordinateTransformation.DegreesToRadians(Fdash);
//Do the first check to see if we have an eclipse
if (Math.Abs(Math.Sin(F)) > 0.36)
{
return(details);
}
double A1 = AASCoordinateTransformation.MapTo0To360Range(299.77 + 0.107408 * k - 0.009173 * T2);
A1 = AASCoordinateTransformation.DegreesToRadians(A1);
details.TimeOfMaximumEclipse = AASMoonPhases.MeanPhase(k);
double DeltaJD = 0;
if (bSolarEclipse)
{
DeltaJD += -0.4075 * Math.Sin(Mdash) +
0.1721 * E * Math.Sin(M);
}
else
{
DeltaJD += -0.4065 * Math.Sin(Mdash) +
0.1727 * E * Math.Sin(M);
}
DeltaJD += 0.0161 * Math.Sin(2 * Mdash) +
-0.0097 * Math.Sin(2 * Fdash) +
0.0073 * E * Math.Sin(Mdash - M) +
-0.0050 * E * Math.Sin(Mdash + M) +
-0.0023 * Math.Sin(Mdash - 2 * Fdash) +
0.0021 * E * Math.Sin(2 * M) +
0.0012 * Math.Sin(Mdash + 2 * Fdash) +
0.0006 * E * Math.Sin(2 * Mdash + M) +
-0.0004 * Math.Sin(3 * Mdash) +
-0.0003 * E * Math.Sin(M + 2 * Fdash) +
0.0003 * Math.Sin(A1) +
-0.0002 * E * Math.Sin(M - 2 * Fdash) +
-0.0002 * E * Math.Sin(2 * Mdash - M) +
-0.0002 * Math.Sin(omega);
details.TimeOfMaximumEclipse += DeltaJD;
double P = 0.2070 * E * Math.Sin(M) +
0.0024 * E * Math.Sin(2 * M) +
-0.0392 * Math.Sin(Mdash) +
0.0116 * Math.Sin(2 * Mdash) +
-0.0073 * E * Math.Sin(Mdash + M) +
0.0067 * E * Math.Sin(Mdash - M) +
0.0118 * Math.Sin(2 * Fdash);
double Q = 5.2207 +
-0.0048 * E * Math.Cos(M) +
0.0020 * E * Math.Cos(2 * M) +
-0.3299 * Math.Cos(Mdash) +
-0.0060 * E * Math.Cos(Mdash + M) +
0.0041 * E * Math.Cos(Mdash - M);
double W = Math.Abs(Math.Cos(Fdash));
details.gamma = (P * Math.Cos(Fdash) + Q * Math.Sin(Fdash)) * (1 - 0.0048 * W);
details.u = 0.0059 +
0.0046 * E * Math.Cos(M) +
-0.0182 * Math.Cos(Mdash) +
0.0004 * Math.Cos(2 * Mdash) +
-0.0005 * Math.Cos(M + Mdash);
//Check to see if the eclipse is visible from the Earth's surface
if (Math.Abs(details.gamma) > (1.5433 + details.u))
{
return(details);
}
//We have an eclipse at this time
details.bEclipse = true;
//In the case of a partial eclipse, calculate its magnitude
double fgamma = Math.Abs(details.gamma);
if (((fgamma > 0.9972) && (fgamma < 1.5433 + details.u)))
{
details.GreatestMagnitude = (1.5433 + details.u - fgamma) / (0.5461 + 2 * details.u);
}
return(details);
}
